I trade off the order book and depth chart on gdax. I bought when I did because I saw the wall on the depth chart and was confident the price was going to upswing when it hit the wall.  There were more buy orders than sell orders at that second. I stuck with my strategy however It didn't work that time. I'm not worried about losing money. I never sell below the price I bought in at. I just wait for it to come back up. Then place my sell order within a few dollars of the wall so I get the execution right before it hits and changes direction.